I have two smaller cousins of the bull, San Diego Gophers and now that my male is adult he does get a rat pup sized a little thicker or about the same as he is every 14-21 days. He measures about 180 cm. My female, who is smaller gets a smaller rat pup every 12 or more days now, she is younger and planned to be bred next year. When they were younger I followed corns snake feeding frequency too and just looked at his girth for prey item size. The females tends to get squishy so thatis why I lessened the frequency to at least 12 days in between feedings. Both my gophers stop eating or skip meals in winter time.
I have read that they need loads of food but mine does well on this frequency. He seems to be looking for food sometimes but that will give him some exercise.
I give them slightly warmer warm spots than my corns and I do provide a warm spot during the night in winter, like I do with my corns, only I start doing that earlier in the season with my gophers since I consider them ore desert like animals. At the other hand, at night is does get quite cold in the desert.... anyway, they do great.